11 31 051

Necessary preliminary tasks:
Remove engine.
Mount engine on assembly stand.
Remove cylinder head cover.
Remove all spark plugs.
Remove tensioning device for drive belt.
Remove vibration damper.
Remove crankshaft seal at front.
Check timing.
Remove the sealing cap of the chain tensioner for the oil pump.
Remove sealing cover for vacuum pump.
Removing oil sump.

Engine removed:
Block crankshaft with special tool 11 9 260 .

Attention!
To release central bolt (1), remove special tool 11 0 300 .

Attention!

Remount special tool 11 4 280 for the S55 engine.

Fasten the special tools 11 4 281 with screws (1).

Release chain tensioner (1).

Tightening torque 11 31 7AZ.

Attention!

Have a cleaning cloth ready. A small quantity of engine oil will emerge after the screw connection has been released.

Make sure no engine oil runs onto belt drive.

Installation note:

Renew the sealing ring.

Release central bolt (1).

Release central bolt (1).

Screw in special tool 11 8 650 on screw connection of belt tensioner on crankcase.

Turn camshaft sprocket with central bolt at crankshaft into position until special tool 11 0 290 can be secured.

Simultaneously secure special tool 11 0 290 to sprocket and special tool 11 8 650 .

Central bolt for camshaft sprocket.

Tightening torque 11 66 2AZ.

Attention!

Before releasing the central bolt on the oil pump, the hydraulic chain tensioner must be drained.

Carefully press tensioning rail (1) with a suitable screwdriver (2) in direction of arrow.

As the oil pressure in the chain tensioner can only be drained pulsating, the tensioning rail (1) must be pressed several times.

Attention!

Breakaway torque of central bolt > 600 Nm.

A 3/4-inch tool (large powered square) is required to release central bolt.

Release central bolt (1) with 3/4-inch tool (2).

Screw in vibration absorber screws (1).

Move hub (2) on crankshaft forward in direction of arrow to remove.

Open screw plug (1).

Tightening torque 11 11 7AZ.

Installation note:

Replace aluminium screws.

Open screw plug (1).

Tightening torque 11 11 8AZ.

Release bearing journal (1) from timing chain module on cylinder head.

Tightening torque 11 31 6AZ.

Release bearing journal (1) from timing chain module on crankcase.

Tightening torque 11 31 5AZ.

Release bolts (1) from timing chain module on cylinder head.

Tightening torque 11 31 4AZ.

Remove chain module with timing chain and camshaft sprocket upwards in direction of arrow.

Note:

Graphic N52.

Press the tensioning rail (1) and hold down.

Chain tensioner piston with a suitable lock pin (2) with a diameter of 2.5 to 3 mm.

Loosen screws (3).

Tightening torque: 11 41 10AZ.

Note:

Sprocket must be blocked in order to release central bolt (1).

Secure special tool 2 303 793 to crankcase.

Release oil pump central bolt (1).

Tightening torque 11 41 9AZ.

Release screws (1).

Remove oil pump drive gear from the drive shaft.

Open screw plug (1).

Tightening torque: 11 11 7AZ.

Installation note:

Renew the sealing ring.

Release aluminium screw (1) with special tool 11 8 640 .

Remove chain module (1) in direction of arrow.

Installation:

Attention!

Renew the camshaft sprocket (2).

Observe direction of installation on the camshaft sprocket (2).

Collar (see arrow) on sprocket (2) points to engine.

Incorrect assembly will result in engine damage.

Push on friction plate (1) without retainers.

Attention!

The engine will incur damage if the friction plates are damaged or are not fitted.

Position module (1) for oil pump drive.

Position module (2) for camshaft drive.

Insert hub (3) for vibration absorber with grip disc.

Insert central bolt (1) with hub for crankshaft.

Tighten down central bolt (1).

Tightening torque 11 21 1AZ.

Replace the central bolt (1) of the intake camshaft.

Replace the central bolt (1) of the exhaust camshaft.

Turn the camshaft sensor wheel (2) in direction of arrow until the retaining pins (1) on the special tool 11 4 290 match up.

11 4 290 Slide on special tool in direction of arrow.

Use bolts to fasten special tool 11 4 290 .Installation note:

Screw in both central bolts.

Release both central bolts 90°.

Pretension timing chain with special tool11 9 340 00 9 250 0,6 Nm Use special tool 00 9 120 to tighten central bolts of intake adjuster.

Tightening torque 11 36 1AZ.

Use special tool 00 9 120 to tighten central bolts of exhaust camshaft adjuster.
Tightening torque 11 36 1AZ.
Check the timings again.
Crank engine twice.
Replace front crankshaft seal.
Renew the sealing cap of the vacuum pump.
Renew the sealing cap for the oil pump drive.
Install oil sump.
Fit cylinder head cover.
Install engine.
Reassemble the vehicle.